Human blood plasma and serum (P/S) samples from clinical studies are often archived by biobanks for future research. Unfortunately P/S samples are not intrinsically stable. Pre-analytical handling and storage conditions can have a dramatic impact on sample measurements, potentially rendering results invalid. While acceptable pre-analytical conditions are generally well defined for FDA approved clinical protein assays, they cannot always be optimally predefined for clinical research studies where samples are to be archived for open-ended future research.
Therefore, improvements in methods and systems for quality control tools (e.g., markers and assays) that allow for retrospective assessment of biobanked sample integrity are desirable. Such tools are particularly important as the practice of biobanking increases worldwide. The few markers currently proposed for this purpose are based on an apparent quantitative loss in a particular target protein without consideration of the molecular root cause. Therefore, their use as markers of biospecimen integrity is questionable.